CHRONIC LATERAL ANKLE INSTABILITY: COMPARISON OF STRESS VIEWS AND MRI WITH ARTHROSCOPY.

Abstract

Background: Stress radiography and more recently magnetic resonance imaging have been used to study the integrity of lateral ankle ligaments in chronic symptomatic instability after injury.

Aim: Our aim was to see if magnetic resonance imaging was as good as examination under anaesthesia and stress radiography, for diagnosing injury to the lateral ankle ligaments.

Study Design: Cross-over study.

Methods: Fifty eight patients, 47 men and 11 women, were included in the study. These were athletes or military personnel with symptomatic instability of the ankle after injury. This cohort of patients had MRI scans, stress radiographs and arthroscopic treatment of their ankle. Integrity of the calcaneo-fibular ligament (CFL) was recorded arthroscopically. The sensitivity, specificity, positive and negative predictive value of MRI and stress views, in assessing integrity of the CFL, were compared against the arthroscopic findings which was considered to be the gold standard.

Results: Stress radiography under anaesthesia and MRI has sensitivities of 94% and 47% and specificities of 98% and 83% for diagnosing injury to the CFL, respectively. Stress radiography has a higher accuracy in diagnosing CFL injuries as compared to MRI.

Conclusion: The results of this study casts doubt on the efficacy of MRI in the diagnosis of serious ankle ligament injuries.